Nautilus Shell,with base

As some of you may know ,I am a metal sculptor who often uses Sacred Geometry in my art and constructions.
I have tackled the challenge of making a (large) NAUTILUS SHELL in stainless steel. I started from the premise that it represented the PHI or Fibonacci spiral. I plotted the spiral on a large piece of paper to make a pattern for the cutting of the metal sheet to make up the two sides of the creatures shell. I have a small sliced REAL nautilus shell,and I placed it on the pattern and simply couldn't find where it mated up...This was rather vexing I can tell you. I'd heard pretty much since I began my studies in Sacred Geometry through the popular literature that the nautilus shell was the QUINTESSENTIAL example of the Fibonacci spiral,but when it came time to accomplish this construction the spiral DID NOT MATCH THE PHI SPIRAL.
Here's a link to a short paper published by the British mathematician John Sharp explaining why...
www.emis.de/journals/NNJ...4n1-pt04.html